Apparatus for producing fastening device



April 24, 1956 R E. s'co'rT 2,742,671

, APPARATUS FOR PRODUCING FASTENING DEVICE Original Filed April 13, 19502 Sheets-Sheet l INVENTOR.

ROBERT E. SCOTT BY /W W ATTORNEYS A ril 24, 1956 R. E. SCOTT 2,742,671

APPARATUS FOR PRQUUCING FASTENING DEVICE Original Filed April 13, 1950 2Sheets-Sheet 2 |5 INVENTOR.

ROBERT E. SCOTT ATTORNE S United StateS" Patmt Divided and thisapplication October 1, 1951, Serial No.2495072 1 Claim. (Cl. 13- 36)This invention relates to apparatus for use in the manufacture offastener elements, and is a division of my copending application SerialNo. 155,666 filed April 13, 1950.

I More particularly the invention concerns itself with a die assemblycapable of producing on a production basis fastener elements having ahead, a shank projecting outwardly from the head, and a body of sealingmaterial at the juncture of the shank with the head. Such fastenerelements are particularly suitable for attaching weather stripping anddecorative metal on the exterior surface of a motor vehicle whilepreventing leaks at the points where holes are provided in the vehiclebody to receive the fastener.

A type of fastener which has found wide use in automobile constructionis illustrated in Figure 4 of the accompanyin'g drawings and comprisesgenerally a single piece of wire formed into a head portion and a shankportion, the shank portion consisting of two legspositionedsubstantially normal to the plane of. the head portion and bowedoutwardly with respect to each other between the head and the tip of theshank. Thetip's of the le s are usually in close proximity to each otherand commonly overlap. y s I l In the attaching of metal trim to anautomobile body, for example, the headpo'rti'o'n engag s the trim andthe legs are forced throii'gh a hole rovided in the body.

In this connection, however, a evere pr blem has been encountered inthat a bad leak is created by the pres h e of the hole whereby water canre'achint'r io'r appointments'as well as interior metal surfaces havenot been protected against eirter'n'al corrosive influences. Attemptshave been made to stop such leaks by the use ofsoft rubber gaskets, butdifficulty has been expe'ri ended i fitting gaskets properlyto the oddshapes which are characteristic of this type of fastener. Suchseparabl'e gaskets, however, carefully formed, permit some leakage alongthe surfaces or the fastener legs. Further, they have an addeddisadvantage in that the ga kets are posh tioned by hand and ma sproduction techni ne'sfsun ii an appreciable number or such gasketsbeing omitted. So'rne of this diniculty stems from carflessness of laborand some from a tearing of the gasket asit fl (I over the bowed portionof the fastener legs. Wha r the reason, however m any fasteners are usedwithout the gask t ier/i ea therefor. I p p g The foregoing difficultiesare overcome herein by providing a fastener of'the general typ'e notedabove with means inthe form of e body sealing material integral- 1ybonded at the juncture of the head with the shank, and it is an objectof this invention to provide a simple, ineirpensive die assemblyrendering" it possible to produce such fastener elements on aneconomical production basis.

l hav e now found that the foregoing and related ob- .b sew d ii a a t nn dev ee owni a t s. and w e mb d'n. ii sa has. was head portion forsaid device and spaced Wires extending 2,742,671 Patented Apr. 24, 19562 outwardly from said mass to form a shank portion for said device, thespaced wires of the shank being bowed outwardly with respect to eachother between the head portion and the tip of the shank and beingyieldably movable with respect to each other.

In the use of a thermoplastic body, the method of forming the fasteningdevice of the invention comprises positioning the thermoplastic materialin contact with the fastener; applying a pressure to the thermoplastic,the pressure having aprincipal vector toward the junction of the headand shank; and heating the thermoplastic sufficiently to cause it toflow into the space surrounding said junction. I

The die assembly for manufacturing the fastener of the invention,wherein the fastener comprises a head .and a shank, comprises a backingmember for the fastener; means for heating the assembly; and a formingdie adapted to press the thermoplastic material against the head andcomprising a plurality of substantially uniformly spaced dimples joinedby flat web portions and being provided with a hole at the center ofeach of said dimples to receive the shank when the forming die ispressed against the head. When a thermoset resin is used in theinvention, the dimples provide a mold space in which the condensingagents are held while the plastic forming reaction is carried out.

Other and more detailed objects of the invention will become apparentfrom a consideration of the following specification, the appended claimand the accompany in'g drawings, throughout the several views of whichlike reference characters'indicate like parts, and wherein:

Figure ,1 illustrates an embodiment of the fastening device of theinvention;

Figure 2 is a cross sectional view of Figure 1 taken through line 2:4;

I Figure '3 is a cross sectional view of Figure 1 taken through the line33;

Figure 4 illustrates an embodiment of the wire portion of the fastenerof the invention;

Figure 5 illustrates a manner of using the fastener of the invention inthe attaching of a decorative molding to an automobile body;

Figure 6 illustrates a die assembly suitable for use in the manufactureofthe fastener;

Figure 7 illustrates an embodiment of the wire portion of the fastenerin a form which can be conveniently stamped from sheet metal;

Figure 8 illustrates an integrally formed wire and thermo'plastic'fastener wherein the wire portion is similar to the structure of Figure7;

Figure 9 illustrates a wire fastener similar to the fastener of Figure:with a modified head portion;

Figure 10 illustrates an integrally formed wir'e and thermoplasticfastener wherein the wire portion is similar to the fastener of Figure9;

Figure 11 illustrates a form of wire fastener which can be convenientlystamped from sheet metal;

12 illustrates an integrally forined wire and thermoplastic fastenerwheiein the wire portion is siinilar to the fastener of Figure 11; v

Figure 13 illustrates a wire fastener sir'nilar to that shownin Figure11 eiicept that a modified head portion is shown;

Figure 14 illustrates an integrally formed wire and thermoplasticfastener wherein the wire portion is similar to that of Figure 13; and

v Fig re 1; illiisti'ate's a the assembly suitable for use portion ofthe fastener of the invention consists generally of a wire head portionand leg portions 11 which are preferably formed from a single piece ofwire as illustrated in Figure 4. A thermoplastic body which consists ofa sheet portion 12, and a dome portion 13 is integrally formed in thefastener in a manner such that the dome portion completely encloses aportion of each of the legs; that is, this portion of the legs isactually embedded in the thermoplastic body. The sheet portion 12 ispisitioned substantially in the plane of the wire portion 10 in a mannersuch that the wire forms an intimately contacting border for the sheet.A tuft 14 of the thermoplastic material is normally deposited at theapex of the dome 13 in the forming operation.

With specific reference to Figure 5, the head portion, comprising thesheet 12 and its wire border 10, is in engagement with a decorativemetal piece 15 while the Wire shank, that is legs 11, is insertedthrough an opening 16 in a portion of an automobile body 17.

widest point between the bowed legs such that the legs, when beinginserted, are forced together as the fastener is inserted andsubsequently spring apart and press against the sides of opening 16. Inthis manner portion of the thermoplastic body are brought to bearagainst the metal surfaces of the automobile body surrounding theopening 16.

Figure 6 illustrates an apparatus suitable for forming the fastener ofthe invention. An upper die plate 18 is provided with openings 19adapted to receive heating elements (19'). The upper die plate 18 isalso provided with recesses 20 and the holes 21 extending inwardly fromthe recesses. A lower die plate or backing plate 22 is provided withopenings 23 adapted to receive heating elements (19). A rubber mat 24 orthe like is shown positioned on the top surface of the backing plate. Aforming die 25 consists of a plate having fiat web portions 26 anddimples 27. Each of the dimples is shaped to conform with the shape ofthe recesses 20 in the upper die plate 18. Each dimple is also providedwith an opening 28 which is adapted to lie concentrically to thecorresponding hole 21 in the upper die plate.

Figures 7, 9, 11 and 13 illustrate the various types of wire fastenerswhich may be used in the present invention. In this connection the wordwire is used broadly to include members other than those with circularcross sections. The particular shape of the cross section of suchelements is not critical to the invention, and the word wire as usedherein is intended to cover threads, filaments, and the like.

With particular reference to Figures 9, 10, 13 and 14 a modified headportion is shown which comprises a member 29 lying substantiallyparallel to and spaced from the head portion 10. These additionalappendages to the head portion have been found useful, as hooks for thefastening of additional elements. The presence or absence of suchappendages is not critical to the invention. Rather, my invention isdirected particularly to the generally L-shaped portion at the junctionof the head and shank.

Figure 15 illustrates a die assembly adapted to make fasteners of thetype shown in Figures 10 and 14. The assembly is similar to that shownin Figure 6 except that an additional backing plate 30 is positionedbelow' the head portion 10. As shown it is most practical to use asingle backing plate to serve two oppositely disposed rows of fasteners.

In the operation of the die assembly of Figure 6 the forming die 25carries the wire portion of the fastener to the apparatus in the mannershown; that is, with the head 10 of the wire portion in engagement withthe fiat portions 25 of the forming die and the legs 11 of the wireportion extending through the opening 28 in the dimple 27. The formingdie, equipped with wire por- The opening 16 has a diameter somewhatsmaller than the tions, is placed over the rubber mat 24 or othersuitable thermoplastic material which is positioned on the lower die.The upper die is then brought down in a manner such that the legs of thefastener wire enter the holes 21 in the upper die plate. When thesurface of the recesses 20 in the upper die plate contact the uppersurface of the dimples, the forming die 25 moves downwardly and forcesthe head portion 10 of the wire through the thermoplastic material 24which may be softened sufficiently to flow by the heating of the dieplates. The thickness of the rubber mat 24 is usually somewhat greaterthan the thickness of the wire of the fastener. In this manner the wireportion 10 cuts its way through the plastic and a portion of the latteris displaced upwardly into the dimple to form the dome and to embed thelower portion of the legs. Excess material, as the tuft 14, is permittedto flow unrestricted through the opening in the dimple, and along thesurfaces of the shank. At the completion of the operation and when theformed plastic is sutlieiently cool so as to retain its shape, theindividual fasteners may then be removed from the resulting matrix.

in the operation of the die assembly of Figure 15 the rubber mat 24 ispositioned above the fastener shanks. The upper die plate 18 is moveddownwardly which in turn causes the forming die 25 to move downwardlyagainst the rubber mat. Shank portions 11 pierce the rubber mat and passthrough the hole 28 into the recesses 21. As the upper die plate andforming die continue downwardly, the rubber mat is pressed against thehead portion 10 and the backing plate 30. This causes the heated rubberto be directed toward the junction of the head and shank portions and totake the shape of the dimple 27. Excess thermoplastic material isallowed to flow unrestricted through the opening 28 and along thesurfaces of the shank.

The head portion of the fastener may be flat or may be curved to adaptitself to the curvature of the materials being fastened. It will beapparent that the thermoplastic body can be formed on a wire headportion which is curved either concavely or convexly in the same manneras described in connection with a flat head portion. Where curved wirehead portions are used, it is necessary merely to effect a correspondingchange in the contour of the backing plate below the positions assumedby the wire of the fastener head. It is necessary that the wire headportion and the surface of the backing plate have substantially the samecurvature in order that a clean cut may be made as the wire movesthrough the thermoplastic material to contact the backing plate.

In uses where it is desired to use a thermoset resin such as aphenol-formaldehyde resin and the like, the reaction mixture of thecondensing agents can be placed in the space between the underside of adimple and the top of the backing plate. In this instance the fastenersare positioned on the backing plate and the forming die containing thedimples is positioned against the fastener heads and with the fastenershank extending upwardly through the holes in the dimples. The reactionmaterial for forming the thermoset resin can be introduced through saidholes and the entire assembly is permitted to stand until the resin hasset up sufficiently to maintain its shape.

Similarly, polymer emulsions and solutions can be inserted into thecavity beneath the dimples to leave a solid plastic residue onevaporation. In this manner foam rubber or other plastic material can bedeposited in intimate contact with the shank and head portions to form afastener of the desired type.

The number of spaced wires in either the shank or head is not criticalto the invention. It has become standard practice to form a shank fromtwo legs, but it will be apparent that three or more legs could be used.The head portion similarly can comprise any number of spaced wires orcan be solid. In this latter connection and as indicated previously, theword wire is used herein to mean any metal strip, filament, thread orthe like which may be formed into the type of fastener described. r

In most uses the plastic body can be limited to a dome shaped portionsimilar to that shownin the drawings. However, many fastener heads, e.g. Figure 4 and Figure 7, appear to be more satisfactory if a portion ofthe plastic body lies in the plane of the head and contacting all thewire portion of the head.

The exact shape of dimensions of either the sheet portion of domeportion of the plastic body is not critical to the invention. Rather, ineach instance they can be adapted to the particular conditionsencountered. For example the width of the dome portion must be such asto completely seal the hole in the sheet which is penetrated by the legsof the fastener. Similarly it'is preferred that the sheet portion of theplastic body have sufficient area to make a suitable frictional contactwith the material surface in engagement therewith and to provide someresistance to displacement of the plastic body.-

The nature of the plastic material is not critical to the invention.However the principal utility of the invention isin creating awatertight seal and therefore a soft rubber has'been found most suitablein most uses. In other uses, however, relatively harder thermoplasticmaterials may be found more desirable. Forexample,.where the fastenermay be subjected to stresses which act on the plastic body, it ispreferred thatplastics presenting a relatively tough wear-resistant,'yet somewhat resilient, surface may be used. The copolymers of vinylchloride are examples of such materials.

The article of the invention has found its greatest use in the securingof ornamental metal strips to the exterior surfacesof motor vehicles,but has also found use in the attachment of weather stripping,gasketing, molding, particularly where a water-tight seal is desired. Inaddition to themore obvious advantages of the integrally formed metaland plastic structure, the article of the invention is more economicalin its application than the combination of wire fasteners and separategasket pieces. The latter not only have to be formed in a separateoperation, but must be fitted to the fasteners usually by hand. Thearticle of the invention also makes unnecessary the use of suchmaterials as cements and the like which are frequently used in order toproduce a water seal.

What I claim as my invention is:

A die assembly for manufacturing integrally formed,

wire and thermoplastic fasteners wherein the fasteners each comprise ahead shaped to provide an open border frame and a shank joined to andprojecting transversely from the head, saidassembly comprising platessupported for relative movement toward and away from each other andadapted to receive therebetween a body of thermoplastic material, aforming member positioned between one of said plates and the body ofthermoplastic material and movable relative to said plates, said memberbeing embossed at a plurality of uniformly spaced points to formrecesses facing the body and having an opening therethrough at the baseof each recess for receiving the shanks of fasteners inserted betweenthe forming member and body of thermoplastic material, said formingmember having flat surfaces facing the other plate and respectivelysurrounding the recesses and said other plate having flat surfacesfacing said forming member and respectively registering with the flatsurfaces of said forming member, and means for heating the assembly,said surfaces being arranged to engage opposite sides of the borderframe of the fasteners thus inserted and to force the border framesthrough the body of thermoplastic material upon relative movement ofsaid plates toward each other, thereby severing the portions of saidbody of thermoplastic material within said border frames from theremainder of the body and displacing a part of the severed portions intothe recesses around the junctures of the shanks and heads of thefasteners, the face of said one plate adjacent to said forming memberhaving recesses positioned to receive the respective embossed 7 portionsof said member and having a clearance space at the base of each recesstherein for receiving the shanks of the fasteners upon relative movementof the plates toward each other.

References Cited in the file of this patent UNITED STATES PATENTS305,564 Bapterosses Sept. 23, 1884 1,621,000 Crowley Mar. '15, 19271,663,587 Dunbar Mar. 27, 1928 r 1,935,942 Conner Nov. 21, 19332,458,327 Wood Jan. 4, 1949 I FOREIGN PATENTS 87,812 Sweden Aug. 24,1935

